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89 result(s) for "Choolani, Mahesh A."
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3D genome organization in the epithelial-mesenchymal transition spectrum
Background The plasticity along the epithelial-mesenchymal transition (EMT) spectrum has been shown to be regulated by various epigenetic repertoires. Emerging evidence of local chromatin conformation changes suggests that regulation of EMT may occur at a higher order of three-dimensional genome level. Results We perform Hi-C analysis and combine ChIP-seq data across cancer cell lines representing different EMT states. We demonstrate that the epithelial and mesenchymal genes are regulated distinctively. We find that EMT genes are regulated within their topologically associated domains (TADs), with only a subset of mesenchymal genes being influenced by A/B compartment switches, indicating topological remodeling is required in the transcriptional regulation of these genes. At the TAD level, epithelial and mesenchymal genes are associated with different regulatory trajectories. The epithelial gene-residing TADs are enriched with H3K27me3 marks in the mesenchymal-like states. The mesenchymal gene-residing TADs, which do not show enrichment of H3K27me3 in epithelial-like states, exhibit increased interaction frequencies with regulatory elements in the mesenchymal-like states. Conclusions We propose a novel workflow coupling immunofluorescence and dielectrophoresis to unravel EMT heterogeneity at single-cell resolution. The predicted three-dimensional structures of chromosome 10, harboring Vimentin, identify cell clusters of different states. Our results pioneer a novel avenue to decipher the complexities underlying the regulation of EMT and may infer the barriers of plasticity in the 3D genome context.
Chorioamnionitis: An Update on Diagnostic Evaluation
Chorioamnionitis remains a major cause of preterm birth and maternal and neonatal morbidity. We reviewed the current evidence for the diagnostic tests of chorioamnionitis and how this relates to clinical practice today. A comprehensive literature search and review was conducted on chorioamnionitis and intra-uterine inflammation. Data from randomized control trials and systematic reviews were prioritized. This review highlights that sterile inflammation plays an important role in chorioamnionitis and that the current tests for chorioamnionitis including clinical criteria, maternal plasma and vaginal biomarkers lack diagnostic accuracy. Concerningly, these tests often rely on detecting an inflammatory response after damage has occurred to the fetus. Care should be taken when interpreting current investigations for the diagnosis of chorioamnionitis and how they guide obstetric/neonatal management. There is an urgent need for further validation of current diagnostic tests and the development of novel, accurate, minimally invasive tests that detect subclinical intra-uterine inflammation.
Transdermal delivery of antenatal steroids to promote fetal lung maturation: Proof of principle data from sheep and non-human primate models
Background Antenatal steroids (ANS) are routinely administered to women at risk of preterm birth to accelerate fetal lung maturation. Despite extensive clinical use, dosing and route of ANS administration remain unoptimized beyond intramuscular (IM) injection. We aimed to undertake a proof-of-principle assessment of transdermal ANS administration for accelerated fetal lung maturation. Methods We formulated and tested a transdermal ANS (betamethasone) patch in ex vivo studies. To confirm in vivo transdermal distribution of the ANS patch, we undertook a 24-h pharmacokinetic study in non-pregnant cynomolgus macaques (NHP). To assess the efficacy of transdermal betamethasone on fetal lung maturation, we used a preterm sheep model of pregnancy comparing postnatal ventilation outcomes. Date mated ewes received either of the following: (i) IM normal saline (Saline Control, n  = 13); (ii) IM ANS (betamethasone) delivery 2 or 8 days post-treatment (2-Day IM ANS, n  = 14; 8-day IM ANS Group, n  = 6); (iii) IM saline + 2 × transdermal ANS (Betamethasone) patches delivery 2 days post-treatment (2-Day ANS Patch, n  = 10); or (iv) IM saline + 2 × transdermal ANS (betamethasone) patches replaced with 2 × new patches after 48 h, delivery 8 days post-treatment (8-Day ANS Patch, n  = 11). Lambs were delivered at 123 ± 1 dGA (term 150 days), then ventilated for 30 min to assess lung maturation status. Arterial blood gas, delivery, and ventilation data were analyzed ( p  < 0.05 significant). Results Transdermal administration of ANS in NHPs achieved rapid plasma accumulation, with a plasma half-life of 8.9 h, similar to that achieved with IM dosing in clinical practice. In preterm sheep, all 2- and 8-day IM and transdermal ANS patch groups had clinically important and statistically significant improvements in ventilation parameters (umbilical PaCO 2 , pH, tidal volume) compared to saline control. Conclusions We demonstrate, for the first time, the potential for using transdermal ANS for preterm fetal lung maturation. Transdermal ANS administration eliminates the need for injections, pain, and infection risk. Moreover, transdermal ANS delivery demonstrates advantages in dose control, continuity of exposure, and potential to remove drug exposure should the risk of preterm birth resolve. Further development of this technology may improve preterm outcomes through delivery of a low dose, constant fetal steroid exposure.
Maternal plasma cell-free RNA as a predictive test for fetal lung maturation
Background A lack of tests to assess fetal development impacts decision making around antenatal steroid use in women at risk of preterm birth. We analyzed the expression of 21 cfRNA targets related to human fetal lung maturation. Discovery studies were performed using maternal and fetal sheep plasma, with results compared to fetal lung mRNA expression. These findings were then validated in first, second, and third trimester human maternal plasma samples. Methods Discovery studies utilized a preterm sheep model of pregnancy. Date mated ewes received saline (control n  = 6), or antenatal steroids (dexamethasone n  = 12) (betamethasone n  = 11) prior to delivery and ventilation. We analyzed the expression of 21 human cfRNA targets related to lung maturation in maternal and fetal sheep plasma and compared this to mRNA expression in fetal lung tissue. Findings were first validated in a separate cohort of sheep exposed to betamethasone ( n  = 8), intraamniotic LPS endotoxin for lung maturation ( n  = 6), or untreated term animals ( n  = 6). Findings were further validated in maternal plasma from a human cohort of uncomplicated term pregnancies ( n  = 10). Delivery and ventilation data were analyzed with ANOVA, Tukey HSD, and Dunnett T3 tests. A Random Forest algorithm identified genes that separated mature from immature fetal lung subgroups and determined AUC values for maternal and fetal cell-free RNA (cfRNA) feature sets to predict fetal lung maturation. Results We demonstrate that the analysis of 21 human cfRNA targets in maternal plasma is highly predictive of fetal lung maturation status across antenatal steroid induced (Dexamethasone AUC = 0.93; Betamethasone AUC = 1) and physiological (AUC = 1) lung development models. Maternal plasma cfRNA expression in the dexamethasone antenatal steroid group closely resembled direct fetal lung tissue mRNA expression. These findings were then validated in human maternal plasma samples (1st vs. 3rd trimester AUC = 0.96; 2nd vs. 3rd trimester AUC = 1). Conclusions Further development of this technology may provide a rapid, minimally invasive, and cost-effective clinical tool to optimize patient selection for initial and repeat courses of antenatal steroids, along with insights into the molecular mechanisms underlying fetal lung development. Graphical Abstract Graphical abstract illustrating the potential future application of maternal plasma cell-free RNA analysis. Created in https://BioRender.com .
Single-nucleotide polymorphisms in dizygotic twin ovine fetuses are associated with discordant responses to antenatal steroid therapy
Background Antenatal steroid (ANS) therapy is given to women at risk of preterm delivery to accelerate fetal lung maturation. However, the benefit of ANS therapy is variable and how maternal and fetal factors contribute to this observed variability is unknown. We aimed to test the degree of concordance in preterm lung function, and correlate this with genomic, transcriptomic, and pharmacokinetic variables in preterm dizygotic twin ovine fetuses. Methods Thirty-one date-mated ewes carrying twin fetuses at 123 ± 1 days’ gestation received maternal intramuscular injections of either (i) 1 × 0.25 mg/kg betamethasone phosphate and acetate (CS1, n  = 11 twin pairs) or (ii) 2 × 0.25 mg/kg betamethasone phosphate and acetate, 24 h apart (CS2, n  = 10 twin pairs) or (iii) 2 × saline, 24 h apart (negative control, n  = 10 twin pairs). Fetuses were surgically delivered 24 h after their final treatment and ventilated for 30 min. Results ANS-exposed female fetuses had lower arterial partial pressure of carbon dioxide (PaCO 2 ) values than male fetuses (76.5 ± 38.0 vs. 97.2 ± 42.5 mmHg), although the observed difference was not statistically significant ( p  = 0.1). Only 52% of ANS-treated twins were concordant for lung maturation responses. There was no difference in fetal lung tissue or plasma steroid concentrations within or between twin pairs. Genomic analysis identified 13 single-nucleotide polymorphisms (SNPs) statistically associated with ANS-responsiveness, including in the proto-oncogene MET and the transcription activator STAT1. Conclusions Twin fetal responses and ANS tissue levels were comparable with those from singleton fetuses in earlier studies. Twin ovine fetuses thus benefit from ANS in a similar manner to singleton fetuses, and a larger dose of betamethasone is not required. Assuming no difference in input from the placental or maternal compartments, fetal lung responses to ANS therapy in dizygotic twin preterm lambs are dependent on the fetus itself. These data suggest a potential heritable role in determining ANS responsiveness.
Maternal stress during pregnancy alters circulating small extracellular vesicles and enhances their targeting to the placenta and fetus
Background Maternal psychological distress during pregnancy can negatively impact fetal development, resulting in long-lasting consequences for the offspring. These effects show a sex bias. The mechanisms whereby prenatal stress induces functional and/or structural changes in the placental-fetal unit remain poorly understood. Maternal circulating small extracellular vesicles (sEVs) are good candidates to act as “stress signals” in mother-to-fetus communication. Using a repetitive restraint-based rat model of prenatal stress, we examined circulating maternal sEVs under stress conditions and tested whether they could target placental-fetal tissues. Results Our mild chronic maternal stress during pregnancy paradigm induced anhedonic-like behavior in pregnant dams and led to intrauterine growth restriction (IUGR), particularly in male fetuses and placentas. The concentration and cargo of maternal circulating sEVs changed under stress conditions. Specifically, there was a significant reduction in neuron-enriched proteins and a significant increase in astrocyte-enriched proteins in blood-borne sEVs from stressed dams. To study the effect of repetitive restraint stress on the biodistribution of maternal circulating sEVs in the fetoplacental unit, sEVs from pregnant dams exposed to stress or control protocol were labeled with DiR fluorescent die and injected into pregnant females previously exposed to control or stress protocol. Remarkably, maternal circulating sEVs target placental/fetal tissues and, under stress conditions, fetal tissues are more receptive to sEVs. Conclusion Our results suggest that maternal circulating sEVs can act as novel mediators/modulators of mother-to-fetus stress communication. Further studies are needed to identify placental/fetal cellular targets of maternal sEVs and characterize their contribution to stress-induced sex-specific placental and fetal changes.
Unravelling the Mystery of Stem/Progenitor Cells in Human Breast Milk
Mammary stem cells have been extensively studied as a system to delineate the pathogenesis and treatment of breast cancer. However, research on mammary stem cells requires tissue biopsies which limit the quantity of samples available. We have previously identified putative mammary stem cells in human breast milk, and here, we further characterised the cellular component of human breast milk. We identified markers associated with haemopoietic, mesenchymal and neuro-epithelial lineages in the cellular component of human breast milk. We found 2.6 ± 0.8% (mean ± SEM) and 0.7 ± 0.2% of the whole cell population (WCP) were found to be CD133+ and CD34+ respectively, 27.8 ± 9.1% of the WCP to be positive for Stro-1 through flow-cytometry. Expressions of neuro-ectodermal stem cell markers such as nestin and cytokeratin 5 were found through reverse-transcription polymerase chain reaction (RT-PCR), and in 4.17 ± 0.2% and 0.9 ± 0.2% of the WCP on flow-cytometry. We also established the presence of a side-population (SP) (1.8 ± 0.4% of WCP) as well as CD133+ cells (1.7 ± 0.5% of the WCP). Characterisation of the sorted SP and non-SP, CD133+ and CD133- cells carried out showed enrichment of CD326 (EPCAM) in the SP cells (50.6 ± 8.6 vs 18.1 ± 6.0, P-value  = 0.02). However, culture in a wide range of in vitro conditions revealed the atypical behaviour of stem/progenitor cells in human breast milk; in that if they are present, they do not respond to established culture protocols of stem/progenitor cells. The identification of primitive cell types within human breast milk may provide a non-invasive source of relevant mammary cells for a wide-range of applications; even the possibility of banking one's own stem cell for every breastfeeding woman.
Maternal exposure to a high-magnitude earthquake during pregnancy influences pre-reading skills in early childhood
Exposure to an adverse prenatal environment can influence fetal development and result in long-lasting changes in the offspring. However, the association between maternal exposure to stressful events during pregnancy and the achievement of pre-reading skills in the offspring is unknown. Here we examined the association between prenatal exposure to the Chilean high-magnitude earthquake that occurred on February 27th, 2010 and the development of early reading precursors skills (listening comprehension, print knowledge, alphabet knowledge, vocabulary, and phonological awareness) in children at kindergarten age. This multilevel retrospective cohort study including 3280 children, of whom 2415 were unexposed and 865 were prenatally exposed to the earthquake shows substantial evidence that maternal exposure to an unambiguously stressful event resulted in impaired pre-reading skills and that a higher detrimental effect was observed in those children who had been exposed to the earthquake during the first trimester of gestation. In addition, females were more significantly affected by the exposure to the earthquake than their male peers in alphabet knowledge; contrarily, males were more affected than females in print knowledge skills. These findings suggest that early intervention programs for pregnant women and/or children exposed to prenatal stress may be effective strategies to overcome impaired pre-reading skills in children.
A biological and ethical assessment of whether humans could or should reproduce in space
Contemporary plans to establish human habitation on the Earth’s Moon have increased interest in the ability of humans to establish extraterrestrial pregnancies. There is a lack of data to identify if humans could safely reproduce away from the Earth, and even less guidance with regard to whether we should attempt to do so. This work was developed to stimulate investigation into the likely biological and ethical challenges facing the establishment and maintenance of a healthy human extraterrestrial pregnancy.
Simulated lunar microgravity transiently arrests growth and induces osteocyte-chondrocyte lineage differentiation in human Wharton’s jelly stem cells
Human Wharton’s jelly stem cells (hWJSCs) are multipotent stem cells that are extensively employed in biotechnology applications. However, the impact of simulated lunar microgravity (sμG) on the growth, differentiation, and viability of this cell population is incompletely characterized. We aimed to determine whether acute (72 h) exposure to sμG elicited changes in growth and lineage differentiation in hWJSCs and if putative changes were maintained once exposure to terrestrial gravity (1.0 G) was restored. hWJSCs were cultured under standard 1.0 G conditions prior to being passaged and cultured under sμG (0.16 G) using a random positioning machine. Relative to control, hWJSCs cultured under sμG exhibited marked reductions in growth but not viability. Cell population expression of characteristic stemness markers (CD 73, 90, 105) was significantly reduced under sμG conditions. hWJSCs had 308 significantly upregulated and 328 significantly downregulated genes when compared to 1.0 G culture conditions. Key markers of cell replication, including MKI67 , were inhibited. Significant upregulation of osteocyte–chondrocyte lineage markers, including SERPINI1, MSX2, TFPI2, BMP6, COMP, TMEM119, LUM, HGF, CHI3L1 and SPP1 , and downregulation of cell fate regulators, including DNMT1 and EZH2 , were detected in sμG-exposed hWJSCs. When returned to 1.0 G for 3 days, sμG-exposed hWJSCs had accelerated growth, and expression of stemness markers increased, approaching normal (i.e. 95%) levels. Our data support earlier findings that acute sμG significantly reduces the cell division potential of hWJSCs and suggest that acute sμG-exposure induces reversible changes in cell growth accompanied by osteocyte–chondrocyte changes in lineage differentiation.